SASKATOON, Saskatchewan, March 23 (Reuters) - The
rising Red River, still days ahead of cresting at
its headwaters, already is forcing some grain
shipments by rail to find new, slower paths to
market.

Burlington Northern Santa Fe (BNI.N) has already
seen washouts along its north-south line in North
Dakota ahead of the Red River crest, forecast to hit
Fargo, N.D. Friday.

The washouts are causing one- to four-day delays for
shipments of agricultural products coming mainly
from Canada, said Suann Lundsberg, spokeswoman for
Burlington.

"It's not a huge problem now, but obviously it can
change," she said.

The flood outlook for the Red River, which runs
north between Minnesota and North Dakota into the
central Canadian province of Manitoba, may worsen
depending on how much more rain falls in the next
few days. Flooding is forecast to rank among the
worst years on record on both sides of the border.

The valley is a key grain-growing region. Rail
shipments are relatively light in spring, but the
flood may affect the western flow of corn and
soybeans to the U.S. Northwest or the eastern path
of wheat to Minneapolis, said Dan Mack,
vice-president of transportation for CHS Inc. (CHSCP.O),
which has a large number of grain elevators in the
Red River valley.

"Typically, you won't flood every rail line but
you'll have interruptions of service," Mack said.
"Some areas may be completely severed."

The length of the rail disruption depends on the
flood's severity, Mack said. Washed-out roads will
also delay grain shipments.

Logistic constraints can drive up the cash prices of
farm commodities if they result in a temporary
shortage, Mack said.

The key grain-moving lines in North Dakota and
western Minnesota are Burlington's north-south line
and Canadian Pacific Railway's (CP.TO) east-west
line, Mack said.

CPR spokesman Mike Lovecchio said he does not expect
problems with that line, which mainly runs west of
the expected flood zone.

A greater concern is CP track south of Manitoba's
largest city of Winnipeg, directly through the Red
River valley, Lovecchio said. CP has increased its
checks for washed-out track and soft rail beds as it
waits for the river crest to move north.

Most grain elevators on the Canadian side of the
valley are above the flood plain, said Bruce
Burnett, director of weather and market analysis for
the Canadian Wheat Board, which markets Western
Canadian wheat and barley.

Transportation in the flooded area will be difficult
but there are alternative paths for grain shipments
to enter the U.S. by rail, Burnett said.

Fargo-based U.S. Agriculture Department official
Dale Ihry has predicted that at least 1 million
acres won't be planted this spring in North Dakota.